They will unlock your phone if you don’t have a passcode and will look through it. If you do have a passcode they will ask you to unlock it so they can look through it and deny you entry if you don’t.

If there are social media accounts with your name on them they will ask you to log into them so they can look through em and deny you entry if you refuse.

This all presupposes that your phone and it’s os are hardened against cellebrite, which if you’re running older android devices or really android devices in general is not the case.

Your best bet is to cancel your phone plan and make a backup of your phone then walk through with a blank phone (“I heard the cell towers are different so I’m gonna go to Verizon to get this one turned on”) and restore the backup and set up a plan after you’re in.

Assuming you have the technical ability to do this, access to the technology required, and the competence under questioning to avoid getting jammed up.

The dumb guy method is to just not walk a phone through. They can’t look at your device if you don’t have it with you.